paul ciancia, a 23-year-old l.a. resident, whom authorities say opened fire with a high-power rifle, inside terminal three early friday morning. >> we have an active shooting in terminal three. >> reporter: witnesses describe a chaotic scene, saying he started shooting right outside the security checkpoint. as police raced in, he made it all the way to the back of the terminal, near the departure gates. passengers ducked for cover. some even hid in a bathroom stall. officers had their guns drawn, yelling at passengers to drop to the floor. >> everybody on the floor. on the floor, now. >> reporter: and after people ran as fast as they could -- >> go, go. >> reporter: the panic and lockdown that followed blocked ambulances from getting close, causing rescuers to race hundreds of yards to get the wounded to safety. witnesses say the shooter was armed with multiple guns. when he ran out of bullets in one, he allegedly grabbed another. >> i heard gunshots. a few weekends later, i saw him come up the elevator, and walk abo